ArgumentPromotion.cpp revision 40c14be5bc9ba900f01c408b65aca57e053788e1
1//===-- ArgumentPromotion.cpp - Promote by-reference arguments ------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This pass promotes "by reference" arguments to be "by value" arguments. In 11// practice, this means looking for internal functions that have pointer 12// arguments. If it can prove, through the use of alias analysis, that an 13// argument is *only* loaded, then it can pass the value into the function 14// instead of the address of the value. This can cause recursive simplification 15// of code and lead to the elimination of allocas (especially in C++ template 16// code like the STL). 17// 18// This pass also handles aggregate arguments that are passed into a function, 19// scalarizing them if the elements of the aggregate are only loaded. Note that 20// it refuses to scalarize aggregates which would require passing in more than 21// three operands to the function, because passing thousands of operands for a 22// large array or structure is unprofitable! 23// 24// Note that this transformation could also be done for arguments that are only 25// stored to (returning the value instead), but does not currently. This case 26// would be best handled when and if LLVM begins supporting multiple return 27// values from functions. 28// 29//===----------------------------------------------------------------------===// 30 31#define DEBUG_TYPE "argpromotion" 32#include "llvm/Transforms/IPO.h" 33#include "llvm/Constants.h" 34#include "llvm/DerivedTypes.h" 35#include "llvm/Module.h" 36#include "llvm/CallGraphSCCPass.h" 37#include "llvm/Instructions.h" 38#include "llvm/ParameterAttributes.h" 39#include "llvm/Analysis/AliasAnalysis.h" 40#include "llvm/Analysis/CallGraph.h" 41#include "llvm/Target/TargetData.h" 42#include "llvm/Support/CallSite.h" 43#include "llvm/Support/CFG.h" 44#include "llvm/Support/Debug.h" 45#include "llvm/ADT/DepthFirstIterator.h" 46#include "llvm/ADT/Statistic.h" 47#include "llvm/ADT/StringExtras.h" 48#include "llvm/Support/Compiler.h" 49#include <set> 50using namespace llvm; 51 52STATISTIC(NumArgumentsPromoted , "Number of pointer arguments promoted"); 53STATISTIC(NumAggregatesPromoted, "Number of aggregate arguments promoted"); 54STATISTIC(NumArgumentsDead , "Number of dead pointer args eliminated"); 55 56namespace { 57 /// ArgPromotion - The 'by reference' to 'by value' argument promotion pass. 58 /// 59 struct VISIBILITY_HIDDEN ArgPromotion : public CallGraphSCCPass { 60 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 61 AU.addRequired<AliasAnalysis>(); 62 AU.addRequired<TargetData>(); 63 CallGraphSCCPass::getAnalysisUsage(AU); 64 } 65 66 virtual bool runOnSCC(const std::vector<CallGraphNode *> &SCC); 67 static char ID; // Pass identification, replacement for typeid 68 ArgPromotion() : CallGraphSCCPass((intptr_t)&ID) {} 69 70 private: 71 bool PromoteArguments(CallGraphNode *CGN); 72 bool isSafeToPromoteArgument(Argument *Arg, bool isByVal) const; 73 Function *DoPromotion(Function *F, 74 SmallPtrSet<Argument*, 8> &ArgsToPromote); 75 }; 76 77 char ArgPromotion::ID = 0; 78 RegisterPass<ArgPromotion> X("argpromotion", 79 "Promote 'by reference' arguments to scalars"); 80} 81 82Pass *llvm::createArgumentPromotionPass() { 83 return new ArgPromotion(); 84} 85 86bool ArgPromotion::runOnSCC(const std::vector<CallGraphNode *> &SCC) { 87 bool Changed = false, LocalChange; 88 89 do { // Iterate until we stop promoting from this SCC. 90 LocalChange = false; 91 // Attempt to promote arguments from all functions in this SCC. 92 for (unsigned i = 0, e = SCC.size(); i != e; ++i) 93 LocalChange |= PromoteArguments(SCC[i]); 94 Changed |= LocalChange; // Remember that we changed something. 95 } while (LocalChange); 96 97 return Changed; 98} 99 100/// PromoteArguments - This method checks the specified function to see if there 101/// are any promotable arguments and if it is safe to promote the function (for 102/// example, all callers are direct). If safe to promote some arguments, it 103/// calls the DoPromotion method. 104/// 105bool ArgPromotion::PromoteArguments(CallGraphNode *CGN) { 106 Function *F = CGN->getFunction(); 107 108 // Make sure that it is local to this module. 109 if (!F || !F->hasInternalLinkage()) return false; 110 111 // First check: see if there are any pointer arguments! If not, quick exit. 112 SmallVector<std::pair<Argument*, unsigned>, 16> PointerArgs; 113 unsigned ArgNo = 0; 114 for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); 115 I != E; ++I, ++ArgNo) 116 if (isa<PointerType>(I->getType())) 117 PointerArgs.push_back(std::pair<Argument*, unsigned>(I, ArgNo)); 118 if (PointerArgs.empty()) return false; 119 120 // Second check: make sure that all callers are direct callers. We can't 121 // transform functions that have indirect callers. 122 for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); 123 UI != E; ++UI) { 124 CallSite CS = CallSite::get(*UI); 125 if (!CS.getInstruction()) // "Taking the address" of the function 126 return false; 127 128 // Ensure that this call site is CALLING the function, not passing it as 129 // an argument. 130 if (UI.getOperandNo() != 0) 131 return false; 132 } 133 134 // Check to see which arguments are promotable. If an argument is promotable, 135 // add it to ArgsToPromote. 136 SmallPtrSet<Argument*, 8> ArgsToPromote; 137 for (unsigned i = 0; i != PointerArgs.size(); ++i) { 138 bool isByVal = F->paramHasAttr(PointerArgs[i].second, ParamAttr::ByVal); 139 if (isSafeToPromoteArgument(PointerArgs[i].first, isByVal)) 140 ArgsToPromote.insert(PointerArgs[i].first); 141 } 142 143 // No promotable pointer arguments. 144 if (ArgsToPromote.empty()) return false; 145 146 Function *NewF = DoPromotion(F, ArgsToPromote); 147 148 // Update the call graph to know that the function has been transformed. 149 getAnalysis<CallGraph>().changeFunction(F, NewF); 150 return true; 151} 152 153/// IsAlwaysValidPointer - Return true if the specified pointer is always legal 154/// to load. 155static bool IsAlwaysValidPointer(Value *V) { 156 if (isa<AllocaInst>(V) || isa<GlobalVariable>(V)) return true; 157 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) 158 return IsAlwaysValidPointer(GEP->getOperand(0)); 159 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) 160 if (CE->getOpcode() == Instruction::GetElementPtr) 161 return IsAlwaysValidPointer(CE->getOperand(0)); 162 163 return false; 164} 165 166/// AllCalleesPassInValidPointerForArgument - Return true if we can prove that 167/// all callees pass in a valid pointer for the specified function argument. 168static bool AllCalleesPassInValidPointerForArgument(Argument *Arg) { 169 Function *Callee = Arg->getParent(); 170 171 unsigned ArgNo = std::distance(Callee->arg_begin(), 172 Function::arg_iterator(Arg)); 173 174 // Look at all call sites of the function. At this pointer we know we only 175 // have direct callees. 176 for (Value::use_iterator UI = Callee->use_begin(), E = Callee->use_end(); 177 UI != E; ++UI) { 178 CallSite CS = CallSite::get(*UI); 179 assert(CS.getInstruction() && "Should only have direct calls!"); 180 181 if (!IsAlwaysValidPointer(CS.getArgument(ArgNo))) 182 return false; 183 } 184 return true; 185} 186 187 188/// isSafeToPromoteArgument - As you might guess from the name of this method, 189/// it checks to see if it is both safe and useful to promote the argument. 190/// This method limits promotion of aggregates to only promote up to three 191/// elements of the aggregate in order to avoid exploding the number of 192/// arguments passed in. 193bool ArgPromotion::isSafeToPromoteArgument(Argument *Arg, bool isByVal) const { 194 // We can only promote this argument if all of the uses are loads, or are GEP 195 // instructions (with constant indices) that are subsequently loaded. 196 bool HasLoadInEntryBlock = false; 197 BasicBlock *EntryBlock = Arg->getParent()->begin(); 198 SmallVector<LoadInst*, 16> Loads; 199 std::vector<SmallVector<ConstantInt*, 8> > GEPIndices; 200 for (Value::use_iterator UI = Arg->use_begin(), E = Arg->use_end(); 201 UI != E; ++UI) 202 if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 203 if (LI->isVolatile()) return false; // Don't hack volatile loads 204 Loads.push_back(LI); 205 HasLoadInEntryBlock |= LI->getParent() == EntryBlock; 206 } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) { 207 if (GEP->use_empty()) { 208 // Dead GEP's cause trouble later. Just remove them if we run into 209 // them. 210 getAnalysis<AliasAnalysis>().deleteValue(GEP); 211 GEP->eraseFromParent(); 212 return isSafeToPromoteArgument(Arg, isByVal); 213 } 214 // Ensure that all of the indices are constants. 215 SmallVector<ConstantInt*, 8> Operands; 216 for (unsigned i = 1, e = GEP->getNumOperands(); i != e; ++i) 217 if (ConstantInt *C = dyn_cast<ConstantInt>(GEP->getOperand(i))) 218 Operands.push_back(C); 219 else 220 return false; // Not a constant operand GEP! 221 222 // Ensure that the only users of the GEP are load instructions. 223 for (Value::use_iterator UI = GEP->use_begin(), E = GEP->use_end(); 224 UI != E; ++UI) 225 if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 226 if (LI->isVolatile()) return false; // Don't hack volatile loads 227 Loads.push_back(LI); 228 HasLoadInEntryBlock |= LI->getParent() == EntryBlock; 229 } else { 230 return false; 231 } 232 233 // See if there is already a GEP with these indices. If not, check to 234 // make sure that we aren't promoting too many elements. If so, nothing 235 // to do. 236 if (std::find(GEPIndices.begin(), GEPIndices.end(), Operands) == 237 GEPIndices.end()) { 238 if (GEPIndices.size() == 3) { 239 DOUT << "argpromotion disable promoting argument '" 240 << Arg->getName() << "' because it would require adding more " 241 << "than 3 arguments to the function.\n"; 242 // We limit aggregate promotion to only promoting up to three elements 243 // of the aggregate. 244 return false; 245 } 246 GEPIndices.push_back(Operands); 247 } 248 } else { 249 return false; // Not a load or a GEP. 250 } 251 252 if (Loads.empty()) return true; // No users, this is a dead argument. 253 254 // If we decide that we want to promote this argument, the value is going to 255 // be unconditionally loaded in all callees. This is only safe to do if the 256 // pointer was going to be unconditionally loaded anyway (i.e. there is a load 257 // of the pointer in the entry block of the function) or if we can prove that 258 // all pointers passed in are always to legal locations (for example, no null 259 // pointers are passed in, no pointers to free'd memory, etc). 260 if (!HasLoadInEntryBlock && !AllCalleesPassInValidPointerForArgument(Arg)) 261 return false; // Cannot prove that this is safe!! 262 263 // Okay, now we know that the argument is only used by load instructions and 264 // it is safe to unconditionally load the pointer. Use alias analysis to 265 // check to see if the pointer is guaranteed to not be modified from entry of 266 // the function to each of the load instructions. 267 268 // Because there could be several/many load instructions, remember which 269 // blocks we know to be transparent to the load. 270 std::set<BasicBlock*> TranspBlocks; 271 272 AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 273 TargetData &TD = getAnalysis<TargetData>(); 274 275 for (unsigned i = 0, e = Loads.size(); i != e; ++i) { 276 // Check to see if the load is invalidated from the start of the block to 277 // the load itself. 278 LoadInst *Load = Loads[i]; 279 BasicBlock *BB = Load->getParent(); 280 281 const PointerType *LoadTy = 282 cast<PointerType>(Load->getOperand(0)->getType()); 283 unsigned LoadSize = (unsigned)TD.getTypeStoreSize(LoadTy->getElementType()); 284 285 if (AA.canInstructionRangeModify(BB->front(), *Load, Arg, LoadSize)) 286 return false; // Pointer is invalidated! 287 288 // Now check every path from the entry block to the load for transparency. 289 // To do this, we perform a depth first search on the inverse CFG from the 290 // loading block. 291 for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) 292 for (idf_ext_iterator<BasicBlock*> I = idf_ext_begin(*PI, TranspBlocks), 293 E = idf_ext_end(*PI, TranspBlocks); I != E; ++I) 294 if (AA.canBasicBlockModify(**I, Arg, LoadSize)) 295 return false; 296 } 297 298 // If the path from the entry of the function to each load is free of 299 // instructions that potentially invalidate the load, we can make the 300 // transformation! 301 return true; 302} 303 304namespace { 305 /// GEPIdxComparator - Provide a strong ordering for GEP indices. All Value* 306 /// elements are instances of ConstantInt. 307 /// 308 struct GEPIdxComparator { 309 bool operator()(const std::vector<Value*> &LHS, 310 const std::vector<Value*> &RHS) const { 311 unsigned idx = 0; 312 for (; idx < LHS.size() && idx < RHS.size(); ++idx) { 313 if (LHS[idx] != RHS[idx]) { 314 return cast<ConstantInt>(LHS[idx])->getZExtValue() < 315 cast<ConstantInt>(RHS[idx])->getZExtValue(); 316 } 317 } 318 319 // Return less than if we ran out of stuff in LHS and we didn't run out of 320 // stuff in RHS. 321 return idx == LHS.size() && idx != RHS.size(); 322 } 323 }; 324} 325 326 327/// DoPromotion - This method actually performs the promotion of the specified 328/// arguments, and returns the new function. At this point, we know that it's 329/// safe to do so. 330Function *ArgPromotion::DoPromotion(Function *F, 331 SmallPtrSet<Argument*, 8> &ArgsToPromote) { 332 333 // Start by computing a new prototype for the function, which is the same as 334 // the old function, but has modified arguments. 335 const FunctionType *FTy = F->getFunctionType(); 336 std::vector<const Type*> Params; 337 338 typedef std::set<std::vector<Value*>, GEPIdxComparator> ScalarizeTable; 339 340 // ScalarizedElements - If we are promoting a pointer that has elements 341 // accessed out of it, keep track of which elements are accessed so that we 342 // can add one argument for each. 343 // 344 // Arguments that are directly loaded will have a zero element value here, to 345 // handle cases where there are both a direct load and GEP accesses. 346 // 347 std::map<Argument*, ScalarizeTable> ScalarizedElements; 348 349 // OriginalLoads - Keep track of a representative load instruction from the 350 // original function so that we can tell the alias analysis implementation 351 // what the new GEP/Load instructions we are inserting look like. 352 std::map<std::vector<Value*>, LoadInst*> OriginalLoads; 353 354 // ParamAttrs - Keep track of the parameter attributes for the arguments 355 // that we are *not* promoting. For the ones that we do promote, the parameter 356 // attributes are lost 357 ParamAttrsVector ParamAttrsVec; 358 const ParamAttrsList *PAL = F->getParamAttrs(); 359 360 unsigned index = 1; 361 for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; 362 ++I, ++index) 363 if (!ArgsToPromote.count(I)) { 364 Params.push_back(I->getType()); 365 if (PAL) { 366 unsigned attrs = PAL->getParamAttrs(index); 367 if (attrs) 368 ParamAttrsVec.push_back(ParamAttrsWithIndex::get(Params.size(), 369 attrs)); 370 } 371 } else if (I->use_empty()) { 372 ++NumArgumentsDead; 373 } else { 374 // Okay, this is being promoted. Check to see if there are any GEP uses 375 // of the argument. 376 ScalarizeTable &ArgIndices = ScalarizedElements[I]; 377 for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; 378 ++UI) { 379 Instruction *User = cast<Instruction>(*UI); 380 assert(isa<LoadInst>(User) || isa<GetElementPtrInst>(User)); 381 std::vector<Value*> Indices(User->op_begin()+1, User->op_end()); 382 ArgIndices.insert(Indices); 383 LoadInst *OrigLoad; 384 if (LoadInst *L = dyn_cast<LoadInst>(User)) 385 OrigLoad = L; 386 else 387 OrigLoad = cast<LoadInst>(User->use_back()); 388 OriginalLoads[Indices] = OrigLoad; 389 } 390 391 // Add a parameter to the function for each element passed in. 392 for (ScalarizeTable::iterator SI = ArgIndices.begin(), 393 E = ArgIndices.end(); SI != E; ++SI) 394 Params.push_back(GetElementPtrInst::getIndexedType(I->getType(), 395 SI->begin(), 396 SI->end())); 397 398 if (ArgIndices.size() == 1 && ArgIndices.begin()->empty()) 399 ++NumArgumentsPromoted; 400 else 401 ++NumAggregatesPromoted; 402 } 403 404 const Type *RetTy = FTy->getReturnType(); 405 406 // Recompute the parameter attributes list based on the new arguments for 407 // the function. 408 if (ParamAttrsVec.empty()) 409 PAL = 0; 410 else 411 PAL = ParamAttrsList::get(ParamAttrsVec); 412 413 // Work around LLVM bug PR56: the CWriter cannot emit varargs functions which 414 // have zero fixed arguments. 415 bool ExtraArgHack = false; 416 if (Params.empty() && FTy->isVarArg()) { 417 ExtraArgHack = true; 418 Params.push_back(Type::Int32Ty); 419 } 420 421 // Construct the new function type using the new arguments. 422 FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg()); 423 424 // Create the new function body and insert it into the module... 425 Function *NF = new Function(NFTy, F->getLinkage(), F->getName()); 426 NF->setCallingConv(F->getCallingConv()); 427 NF->setParamAttrs(PAL); 428 if (F->hasCollector()) 429 NF->setCollector(F->getCollector()); 430 F->getParent()->getFunctionList().insert(F, NF); 431 432 // Get the alias analysis information that we need to update to reflect our 433 // changes. 434 AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 435 436 // Loop over all of the callers of the function, transforming the call sites 437 // to pass in the loaded pointers. 438 // 439 std::vector<Value*> Args; 440 while (!F->use_empty()) { 441 CallSite CS = CallSite::get(F->use_back()); 442 Instruction *Call = CS.getInstruction(); 443 444 // Loop over the operands, inserting GEP and loads in the caller as 445 // appropriate. 446 CallSite::arg_iterator AI = CS.arg_begin(); 447 for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); 448 I != E; ++I, ++AI) 449 if (!ArgsToPromote.count(I)) 450 Args.push_back(*AI); // Unmodified argument 451 else if (!I->use_empty()) { 452 // Non-dead argument: insert GEPs and loads as appropriate. 453 ScalarizeTable &ArgIndices = ScalarizedElements[I]; 454 for (ScalarizeTable::iterator SI = ArgIndices.begin(), 455 E = ArgIndices.end(); SI != E; ++SI) { 456 Value *V = *AI; 457 LoadInst *OrigLoad = OriginalLoads[*SI]; 458 if (!SI->empty()) { 459 V = new GetElementPtrInst(V, SI->begin(), SI->end(), 460 V->getName()+".idx", Call); 461 AA.copyValue(OrigLoad->getOperand(0), V); 462 } 463 Args.push_back(new LoadInst(V, V->getName()+".val", Call)); 464 AA.copyValue(OrigLoad, Args.back()); 465 } 466 } 467 468 if (ExtraArgHack) 469 Args.push_back(Constant::getNullValue(Type::Int32Ty)); 470 471 // Push any varargs arguments on the list 472 for (; AI != CS.arg_end(); ++AI) 473 Args.push_back(*AI); 474 475 Instruction *New; 476 if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) { 477 New = new InvokeInst(NF, II->getNormalDest(), II->getUnwindDest(), 478 Args.begin(), Args.end(), "", Call); 479 cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv()); 480 cast<InvokeInst>(New)->setParamAttrs(PAL); 481 } else { 482 New = new CallInst(NF, Args.begin(), Args.end(), "", Call); 483 cast<CallInst>(New)->setCallingConv(CS.getCallingConv()); 484 cast<CallInst>(New)->setParamAttrs(PAL); 485 if (cast<CallInst>(Call)->isTailCall()) 486 cast<CallInst>(New)->setTailCall(); 487 } 488 Args.clear(); 489 490 // Update the alias analysis implementation to know that we are replacing 491 // the old call with a new one. 492 AA.replaceWithNewValue(Call, New); 493 494 if (!Call->use_empty()) { 495 Call->replaceAllUsesWith(New); 496 New->takeName(Call); 497 } 498 499 // Finally, remove the old call from the program, reducing the use-count of 500 // F. 501 Call->eraseFromParent(); 502 } 503 504 // Since we have now created the new function, splice the body of the old 505 // function right into the new function, leaving the old rotting hulk of the 506 // function empty. 507 NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList()); 508 509 // Loop over the argument list, transfering uses of the old arguments over to 510 // the new arguments, also transfering over the names as well. 511 // 512 for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(), 513 I2 = NF->arg_begin(); I != E; ++I) 514 if (!ArgsToPromote.count(I)) { 515 // If this is an unmodified argument, move the name and users over to the 516 // new version. 517 I->replaceAllUsesWith(I2); 518 I2->takeName(I); 519 AA.replaceWithNewValue(I, I2); 520 ++I2; 521 } else if (I->use_empty()) { 522 AA.deleteValue(I); 523 } else { 524 // Otherwise, if we promoted this argument, then all users are load 525 // instructions, and all loads should be using the new argument that we 526 // added. 527 ScalarizeTable &ArgIndices = ScalarizedElements[I]; 528 529 while (!I->use_empty()) { 530 if (LoadInst *LI = dyn_cast<LoadInst>(I->use_back())) { 531 assert(ArgIndices.begin()->empty() && 532 "Load element should sort to front!"); 533 I2->setName(I->getName()+".val"); 534 LI->replaceAllUsesWith(I2); 535 AA.replaceWithNewValue(LI, I2); 536 LI->eraseFromParent(); 537 DOUT << "*** Promoted load of argument '" << I->getName() 538 << "' in function '" << F->getName() << "'\n"; 539 } else { 540 GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back()); 541 std::vector<Value*> Operands(GEP->op_begin()+1, GEP->op_end()); 542 543 Function::arg_iterator TheArg = I2; 544 for (ScalarizeTable::iterator It = ArgIndices.begin(); 545 *It != Operands; ++It, ++TheArg) { 546 assert(It != ArgIndices.end() && "GEP not handled??"); 547 } 548 549 std::string NewName = I->getName(); 550 for (unsigned i = 0, e = Operands.size(); i != e; ++i) 551 if (ConstantInt *CI = dyn_cast<ConstantInt>(Operands[i])) 552 NewName += "." + CI->getValue().toStringUnsigned(10); 553 else 554 NewName += ".x"; 555 TheArg->setName(NewName+".val"); 556 557 DOUT << "*** Promoted agg argument '" << TheArg->getName() 558 << "' of function '" << F->getName() << "'\n"; 559 560 // All of the uses must be load instructions. Replace them all with 561 // the argument specified by ArgNo. 562 while (!GEP->use_empty()) { 563 LoadInst *L = cast<LoadInst>(GEP->use_back()); 564 L->replaceAllUsesWith(TheArg); 565 AA.replaceWithNewValue(L, TheArg); 566 L->eraseFromParent(); 567 } 568 AA.deleteValue(GEP); 569 GEP->eraseFromParent(); 570 } 571 } 572 573 // Increment I2 past all of the arguments added for this promoted pointer. 574 for (unsigned i = 0, e = ArgIndices.size(); i != e; ++i) 575 ++I2; 576 } 577 578 // Notify the alias analysis implementation that we inserted a new argument. 579 if (ExtraArgHack) 580 AA.copyValue(Constant::getNullValue(Type::Int32Ty), NF->arg_begin()); 581 582 583 // Tell the alias analysis that the old function is about to disappear. 584 AA.replaceWithNewValue(F, NF); 585 586 // Now that the old function is dead, delete it. 587 F->eraseFromParent(); 588 return NF; 589} 590